The instant-heat water heater
An electric instantaneous water heater for hot tap water offers advantages over a conventional (kitchen) water heater. An instantaneous water heater does not suffer from waiting times, as with a combi boiler, or from standby heat loss, as with a conventional water heater. Furthermore, no inlet combination is required, and therefore no connection to a drain is necessary. Since the product only needs to heat water when in use, comfort is higher and energy consumption is lower.
"Standby loss" refers to the heat lost by the water heater while it is idle, before the water needs to be reheated. For a typical 10-liter kitchen water heater, this can easily amount to 40 W/h—or 345 kWh per year.
Comfort
The downside, however, is that the electrical connection in the home must be capable of handling the brief spikes in power consumption caused by these units. Another drawback is a limited hot water flow rate relative to the appliance’s high electrical rating. To give an example: to shower with an electrically heated unit that offers comfort (hot water flow rate) comparable to a CW4 central heating boiler, you’ll quickly need 18 kW of electrical power. For comparable comfort with a CW5, that’s 27 kW! In addition to a 3x50A electrical connection, many residential distribution panels (circuit breaker boxes) are not designed for these currents and must be modified where possible. In this case, the costs do not outweigh the benefits. A storage tank with a capacity of, for example, 80–120 liters is a much better and cheaper solution in these cases.
The Electric Boiler: A Modern Approach to Heating.
In the Netherlands, the majority of homes still use central heating. Central heating typically involves a distribution system consisting of radiators or underfloor heating through which water flows. The traditional central heating boiler, which burns natural gas, is typically used to heat this water. An electric central heating boiler, on the other hand, also uses water in radiators but does not use natural gas. Instead, the water is heated by one or more electric heating elements.
Electric (Primary) Heating
It is not the most efficient way to heat a space. However, it can be a viable solution for small rooms and areas. It is important to ensure that the use of electric heating does not overload the electrical system. Electric heating is not very energy-efficient and therefore only becomes a viable option if you already have a solar system that generates a surplus of electricity. This will be particularly relevant once the net metering scheme is phased out. We would be happy to explore the options for you and provide advice where necessary.
Can you save on energy costs with an electric boiler?
A comparison between an electric boiler or electric radiant floor heating and a natural gas boiler currently shows that electric heating is not more cost-effective. In fact, the energy costs for heating an average home with an electric boiler are significantly higher than with a natural gas boiler. In terms of energy efficiency, this boils down to the fact that 1 m³ of gas provides roughly the same amount of energy as 9 kWh of electricity in an electric boiler.
Sample calculation.
The cost of 1 m³ of gas is around €1.40, while the cost of 9 kWh of electricity is approximately €3.42. If you choose to heat your home entirely with an electric boiler, you’ll end up paying nearly two and a half times as much as you would with a natural gas boiler. *Prices as of Jan 2024
Although solar panels can generate some of the electricity needed, their efficiency is limited. After all, heat demand is highest during the winter months, but electricity output from solar panels is lowest. As long as the net metering scheme remains in place, using self-generated electricity for electric heating is not cost-effective. However, if the net metering scheme is discontinued, using self-generated electricity for heating could be worthwhile.
Is my home suitable for an electric boiler?
Not every home is suitable for an electric boiler. Most homes have a main electrical connection with a 1×35 or 1×40-amp fuse. An electric boiler designed to heat an entire home requires a three-phase connection with a fuse rating of at least 3×25 amps, but typically 3×35 amps. This connection must be requested from the utility provider and incurs additional costs.
Electric Heating: Not Always a Good Idea.
An electric boiler for heating an entire home is often not only more expensive to operate but is also frequently prohibited by law due to stricter building codes. Nevertheless, (partially) electric heating is not always a bad choice. In situations where certain rooms are used only sporadically, electric heating can be efficient and comfortable, even though it cannot be considered a serious alternative to a natural gas high-efficiency boiler.
Electric Heating and the Building Code
Article 2 of the Housing Act stipulates that rules regarding the safety, health, usability, energy efficiency, and environmental impact of buildings are to be laid down by Order in Council. These rules are set forth in the 2012 Building Decree. All structures in the Netherlands must comply with these rules, including both new and existing buildings.
Since January 1, 2021, the Netherlands has been using a new calculation method to determine the energy performance of buildings. The new calculation method is called NTA 8800. A building’s energy performance, calculated using NTA 8800, must comply with the European Energy Performance of Buildings Directive (EPBD).
The new method replaces several existing methods for new and existing buildings, namely NEN 7120, Nader Voorschrift, and ISSO 75.3. NTA 8800 follows European standards and replaces the current EPC and EI indicators with the annual energy demand per square meter (kWh/m²·year).
Article 6.55a of the Building Regulations states that a home’s heating system may not use more than 1.31 kWh of energy to generate 1 kWh of heat. Electric boilers generally do not meet this requirement and are therefore usually not permitted.
New construction: nearly energy-neutral (BENG)
For all new construction—both residential and non-residential—planning permit applications submitted on or after January 1, 2021, must comply with the requirements for nearly zero-energy buildings (BENG). The requirements set a maximum limit on energy demand and primary fossil fuel consumption, and a minimum requirement for the share of renewable energy. These three requirements are determined based on NTA 8800. BENG stems from the Energy Agreement for Sustainable Growth and the European Energy Performance of Buildings Directive (EPBD). An introductory video about BENG can be viewed and downloaded at:www.rvo.nl/BENG.
Effective January 2024, the Building Decree will be replaced by the Building and Living Environment Decree (Bbl). The Bbl is the new guideline for the construction industry: it sets out the requirements that buildings must meet in order to ensure the necessary quality and safety.
You can find more information on this topic on the U.S. government’s website.
https://www.rvo.nl/onderwerpen/wetten-en-regels-gebouwen/energieprestatie-eisen-verbouw-renovatie